1. Field of the Invention
The present invention relates to an ion implanter and an ion implantation method.
2. Description of the Related Art
A mechanical scanning type ion implanter having an energy analyzer electromagnet located immediately before an end station is known. In this ion implanter, the energy analyzer electromagnet is configured to provide an ion beam implantation tilt angle to a wafer by means of ion beam deflection thereof.
A beamline of the ion implanter is provided with various beamline components to transport an ion beam from an ion source to a workpiece such as the wafer appropriately. At the time of manufacturing the ion implanter, these beamline components are installed at designed positions as precisely as possible. However, in actual cases, some of the components may be arranged at the installation positions with slight errors. Such installation errors may cause an error (hereinbelow also referred to as a trajectory error) of an actual center trajectory (hereinbelow also referred to as an actual trajectory) of the transported ion beam against a designed center trajectory (hereinbelow also referred to as a reference trajectory) of the ion beam.
For example, consider a case in which a beam adjusting component (e.g., a quadrupole lens) configured to adjust focusing or defocusing of the ion beam is installed in a direction perpendicular to the reference trajectory to slightly deviate from the reference trajectory. When the ion beam is incident to this beam adjusting component along the reference trajectory, the ion beam will pass through a place slightly deviating from a center of the beam adjusting component. Consequently, the ion beam is slightly deflected from the reference trajectory due to a focusing or defocusing effect of the beam adjusting component.
Such a trajectory error may be enlarged during transportation of the ion beam toward the workpiece. For example, the trajectory error may be further enlarged during the transportation when a distance from a position at which the trajectory error occurs to the workpiece is longer. Also, in a case in which several beamline components respectively have the installation errors, the trajectory error may be enlarged by combination thereof even when each of the errors is slight. When the trajectory error is large, an influence on precision of an implantation position or an implantation angle of the ion beam to the workpiece cannot be ignored.